U.S. patent application number 12/748518 was filed with the patent office on 2011-03-31 for valve opening/closing timing control device.
This patent application is currently assigned to AISIN SEIKI KABUSHIKI KAISHA. Invention is credited to Masaki KOBAYASHI, Kenji Nonaka.
Application Number | 20110073055 12/748518 |
Document ID | / |
Family ID | 43333228 |
Filed Date | 2011-03-31 |
United States Patent
Application |
20110073055 |
Kind Code |
A1 |
KOBAYASHI; Masaki ; et
al. |
March 31, 2011 |
VALVE OPENING/CLOSING TIMING CONTROL DEVICE
Abstract
A valve opening/closing timing control device includes: a
driving side rotational member synchronously rotatable with a
crankshaft of an internal combustion engine; a driven side
rotational member arranged coaxially with the driving side
rotational member and synchronously rotatable with a camshaft that
opens and closes any one of intake and exhaust valves of the
internal combustion engine; a phase converting mechanism displacing
a relative phase between the driving side rotational member and the
driven side rotational member to an advanced angle phase side or a
retarded angle phase side by distributing an operating fluid to
each of two kinds of pressure chambers, the volume of which is
complementarily varied by a movable partition; and a biasing member
biasing the relative phase toward a predetermined phase suitable
for a start-up of the internal combustion engine except for a most
advanced angle phase and a most retarded angle phase.
Inventors: |
KOBAYASHI; Masaki;
(Okazaki-shi, JP) ; Nonaka; Kenji; (Chiryu-shi,
JP) |
Assignee: |
AISIN SEIKI KABUSHIKI
KAISHA
Kariya-shi
JP
|
Family ID: |
43333228 |
Appl. No.: |
12/748518 |
Filed: |
March 29, 2010 |
Current U.S.
Class: |
123/90.17 |
Current CPC
Class: |
F01L 1/3442 20130101;
F01L 2001/0478 20130101; F01L 2001/34483 20130101; F01L 2001/34453
20130101 |
Class at
Publication: |
123/90.17 |
International
Class: |
F01L 1/34 20060101
F01L001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 25, 2009 |
JP |
2009-220652 |
Claims
1. A valve opening/closing timing control device comprising: a
driving side rotational member synchronously rotatable with a
crankshaft of an internal combustion engine; a driven side
rotational member arranged coaxially with the driving side
rotational member and synchronously rotatable with a camshaft that
opens and closes any one of intake and exhaust valves of the
internal combustion engine; a phase converting mechanism displacing
a relative phase between the driving side rotational member and the
driven side rotational member to an advanced angle phase side or a
retarded angle phase side by distributing an operating fluid to
each of two kinds of pressure chambers, the volume of which is
complementarily varied by a movable partition; and a biasing member
biasing the relative phase toward a predetermined phase suitable
for a start-up of the internal combustion engine except for a most
advanced angle phase and a most retarded angle phase.
2. The valve opening/closing timing control device according to
claim 1, wherein the biasing member includes a first biasing member
to bias the relative phase in a direction of the advanced angle
phase and a second biasing member to bias the relative phase in a
direction of the retarded angle phase, and the valve
opening/closing timing control device further includes a first
restricting portion to define the biasing force of the first basing
member between the predetermined phase and the most retarded angle
phase, and a second restricting portion to define the biasing force
of the second biasing member between the predetermined phase and
the most advanced angle phase.
3. The valve opening/closing timing control device according to
claim 1, wherein the biasing member has the biasing force against a
displacing force acting on the driven side rotational member based
on torque fluctuation of the camshaft.
4. The valve opening/closing timing control device according to
claim 2, wherein the biasing member has the biasing force against a
displacing force acting on the driven side rotational member based
on torque fluctuation of the camshaft.
5. The valve opening/closing timing control device according to
claim 1, wherein the biasing member is a spring placed between the
driving side rotational member and the driven side rotational
member.
6. The valve opening/closing timing control device according to
claim 2, wherein the biasing member is a spring placed between the
driving side rotational member and the driven side rotational
member.
7. The valve opening/closing timing control device according to
claim 3, wherein the biasing member is a spring placed between the
driving side rotational member and the driven side rotational
member.
8. The valve opening/closing timing control device according to
claim 2, wherein a front plate and a rear plate are fixed to the
driving side rotational member, and both of the first biasing
member and the second biasing member are disposed between the
driven side rotational member and the front plate or between the
driven side rotational member and the rear plate.
9. The valve opening/closing timing control device according to
claim 4, wherein a front plate and a rear plate are fixed to the
driving side rotational member, and both of the first biasing
member and the second biasing member are disposed between the
driven side rotational member and the front plate or between the
driven side rotational member and the rear plate.
10. The valve opening/closing timing control device according to
claim 6, wherein a front plate and a rear plate are fixed to the
driving side rotational member, and both of the first biasing
member and the second biasing member are disposed between the
driven side rotational member and the front plate or between the
driven side rotational member and the rear plate.
11. The valve opening/closing timing control device according to
claim 7, wherein a front plate and a rear plate are fixed to the
driving side rotational member, and both of the first biasing
member and the second biasing member are disposed between the
driven side rotational member and the front plate or between the
driven side rotational member and the rear plate.
12. The valve opening/closing timing control device according to
claim 2, wherein a front plate and a rear plate are fixed to the
driving side rotational member, the first biasing member is
disposed either between the driven side rotational member and the
front plate or between the driven side rotational member and the
rear plate, and the second biasing member is disposed either
between the driven side rotational member and the front plate or
between the driven side rotational member and the rear plate.
13. The valve opening/closing timing control device according to
claim 4, wherein a front plate and a rear plate are fixed to the
driving side rotational member, the first biasing member is
disposed either between the driven side rotational member and the
front plate or between the driven side rotational member and the
rear plate, and the second biasing member is disposed either
between the driven side rotational member and the front plate or
between the driven side rotational member and the rear plate.
14. The valve opening/closing timing control device according to
claim 6, wherein a front plate and a rear plate are fixed to the
driving side rotational member, the first biasing member is
disposed either between the driven side rotational member and the
front plate or between the driven side rotational member and the
rear plate, and the second biasing member is disposed either
between the driven side rotational member and the front plate or
between the driven side rotational member and the rear plate.
15. The valve opening/closing timing control device according to
claim 7, wherein a front plate and a rear plate are fixed to the
driving side rotational member, the first biasing member is
disposed either between the driven side rotational member and the
front plate or between the driven side rotational member and the
rear plate, and the second biasing member is disposed either
between the driven side rotational member and the front plate or
between the driven side rotational member and the rear plate.
16. A valve opening/closing timing control device comprising: a
driving side rotational member synchronously rotatable with a
crankshaft of an internal combustion engine; a driven side
rotational member arranged coaxially with the driving side
rotational member and synchronously rotatable with a camshaft that
opens and closes any one of intake and exhaust valves of the
internal combustion engine; a retarded angle chamber and an
advanced angle chamber formed by the driving side rotational member
and the driven side rotational member, in which the retarded angle
chamber moves a relative phase of the driven side rotational member
to the driving side rotational member in a retarded angle direction
as a volume thereof is enlarged, and the advanced angle chamber
moves the relative phase in an advanced angle direction as a volume
thereof is enlarged; and a biasing member biasing the relative
phase toward a predetermined phase except for a most advanced angle
phase and a most retarded angle phase.
17. The valve opening/closing timing control device according to
claim 8, wherein the biasing member includes a first biasing member
to bias the relative phase in a first predetermined phase which is
positioned in a direction of an advanced angle phase than the most
retarded angle phase, and a second biasing member to bias the
relative phase in a second predetermined phase which is positioned
in a direction of a retarded angle phase than the most advanced
angle phase; the first biasing member biases the relative phase
from the most retarded angle phase to the first predetermined phase
and does not bias the relative phase from the first predetermined
phase to the most advanced angle phase; and the second biasing
member biases the relative phase from the most advanced angle phase
to the second predetermined phase and does not bias the relative
phase from the second predetermined phase to the most retarded
angle phase.
18. The valve opening/closing timing control device according to
claim 17, wherein a front plate and a rear plate are fixed to the
driving side rotational member, and both of the first biasing
member and the second biasing member are disposed between the
driven side rotational member and the front plate or between the
driven side rotational member and the rear plate.
19. The valve opening/closing timing control device according to
claim 17, wherein a front plate and a rear plate are fixed to the
driving side rotational member, the first biasing member is
disposed either between the driven side rotational member and the
front plate or between the driven side rotational member and the
rear plate, and the second biasing member is disposed either
between the driven side rotational member and the front plate or
between the driven side rotational member and the rear plate.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims priority under 35
U.S.C. .sctn.119 to Japanese Patent Application 2009-220652, filed
on Sep. 25, 2009, the entire content of which is incorporated
herein by reference.
TECHNICAL FIELD
[0002] This disclosure relates to a valve opening/closing timing
control device including a driving side rotational member
synchronously rotatable with a crankshaft of an internal combustion
engine, a driven side rotational member arranged coaxially with the
driving side rotational member and synchronously rotatable with a
camshaft that opens and closes at least any one of intake and
exhaust valves of the internal combustion engine, and a phase
converting mechanism displacing a relative phase between the
driving side rotational member and the driven side rotational
member by distributing an operating fluid to each of two kinds of
pressure chambers, the volume of which is complementarily varied by
a movable partition.
BACKGROUND DISCUSSION
[0003] JP-A-2009-074384 (Patent Document 1; paragraphs 0009 and
0029, FIGS. 1, 2 and 3) is provided as literature information of
the related art concerning a valve opening/closing timing control
device. The valve opening/closing timing control device disclosed
in Patent Document 1 includes a lock mechanism capable of locking a
relative phase to an intermediate phase which is suitable for
starting of an internal combustion engine, if necessary. The lock
mechanism has a lock groove formed in the driven side rotational
member, and a lock pin movably supported by the driving side
rotational member so as to be fitted into the lock groove. The lock
pin is biased by a spring in a direction of fitting the lock pin
into the lock groove. If the relative phase of both rotational
members reaches the intermediate phase, the lock pin automatically
enters the lock groove by a biasing force of the spring. After the
starting of the internal combustion engine is completed, the
locking state of the lock mechanism is generally released by a
pressure of oil supplied from an oil pump or the like, and,
simultaneously, a displacement operation from the intermediate
phase to an advanced angle side is performed by the pressure of the
oil.
[0004] In general, there are many cases in which the valve
opening/closing timing control device is provided with a biasing
mechanism, such as a torsion spring, for biasing the relative phase
in a direction of the intermediate phase, as a means for
suppressing a tendency in which the driven side rotational member
is retarded with respect to the driving side rotational member by a
reaction force of a cam received from a valve spring of the intake
valve or the exhaust valve. In particular, according to the torsion
spring of the valve opening/closing timing control device disclosed
in Patent Document 1, since its biasing function is defined between
an intermediate control phase which is positioned at a retarded
angle phase direction side than the intermediate phase, and a most
retarded angle phase, and the biasing function is not effective in
a region between an advanced angle phase and the intermediate
phase, a displacement operation from the advanced angle phase to
the intermediate phase or the intermediate control phase is quickly
performed by the reaction force of the cam and an oil pressure of
the pump.
[0005] However, in the valve opening/closing timing control device
disclosed in Patent Document 1, since the lock operation to the
intermediate phase depends upon entry operation of the lock pin
when it reaches the intermediate phase, for example, if the
movement of the lock pin is interfered with by foreign substances
existing in the oil, the lock pin is not reliably fitted into the
lock groove. Therefore, the lock may not be sufficiently displaced
to the intermediate phase.
[0006] After the starting of the internal combustion engine is
completed at the intermediate phase, in order to displace the
relative phase from the intermediate phase to the advanced angle
phase, there is a need for an oil supply mechanism or the like to
push the lock pin out from the lock groove. Therefore, the valve
opening/closing timing control device has a tendency to become
larger and be complicated.
[0007] A need thus exists for a valve opening/closing timing
control device which is not susceptible to the drawback mentioned
above.
SUMMARY
[0008] According to a first aspect of this disclosure, a valve
opening/closing timing control device includes a driving side
rotational member synchronously rotatable with a crankshaft of an
internal combustion engine, a driven side rotational member
arranged coaxially with the driving side rotational member and
synchronously rotatable with a camshaft that opens and closes any
one of intake and exhaust valves of the internal combustion engine,
a phase converting mechanism displacing a relative phase between
the driving side rotational member and the driven side rotational
member toward an advanced angle phase side or a retarded angle
phase side by distributing an operating fluid to each of two kinds
of pressure chambers, the volume of which is complementarily varied
by a movable partition, and a biasing member biasing the relative
phase toward a predetermined phase suitable for a start-up of the
internal combustion engine except for a most advanced angle phase
and a most retarded angle phase.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The foregoing and additional features and characteristics of
this disclosure will become more apparent from the following
detailed description considered with the reference to the
accompanying drawings, wherein:
[0010] FIG. 1 is a cross-sectional view illustrating an overall
structure of a valve opening/closing timing control device
according to a first embodiment;
[0011] FIG. 2 is a cross-sectional view of the valve
opening/closing timing control device in a predetermined phase
taken along the line II-II in FIG. 1;
[0012] FIGS. 3A and 3B are cross-sectional views taken along the
line IIIa-IIIa and IIIb-IIIb in the state of FIG. 2;
[0013] FIG. 4 is a cross-sectional view of the valve
opening/closing timing control device at a most retarded angle
phase taken along the line II-II in FIG. 1;
[0014] FIGS. 5A and 5B are cross-sectional views taken along the
line IIIa-IIIa and IIIb-IIIb in the state of FIG. 4;
[0015] FIG. 6 is a cross-sectional view of the valve
opening/closing timing control device at a most advanced angle
phase taken along the line II-II in FIG. 1;
[0016] FIGS. 7A and 7B are cross-sectional views taken along the
line IIIa-IIIa and IIIb-IIIb in the state of FIG. 6;
[0017] FIG. 8 is an exploded perspective view of major parts of the
valve opening/closing timing control device according to the first
embodiment;
[0018] FIGS. 9A and 9B are views illustrating a valve
opening/closing timing control device according to a second
embodiment which correspond to FIGS. 3A and 3B;
[0019] FIGS. 10A and 10B are views illustrating the valve
opening/closing timing control device according to the second
embodiment which correspond to FIGS. 5A and 5B;
[0020] FIGS. 11A and 11B are views illustrating the valve
opening/closing timing control device according to the second
embodiment which correspond to FIGS. 7A and 7B;
[0021] FIG. 12 is an exploded perspective view of major parts of
the valve opening/closing timing control device according to the
second embodiment;
[0022] FIG. 13 is a cross-sectional view illustrating an overall
structure of a valve opening/closing timing control device
according to a third embodiment;
[0023] FIGS. 14A and 14B are cross-sectional views taken along the
line XIVa-XIVa and XIVb-XIVb in FIG. 13 in a predetermined phase
state;
[0024] FIG. 15 is an exploded perspective view of major parts of a
valve opening/closing timing control device according to a fourth
embodiment; and
[0025] FIGS. 16A and 16B are operation diagrams of major parts of a
valve opening/closing timing control device according to a fifth
embodiment.
DETAILED DESCRIPTION
[0026] Embodiments disclosed here will now be described with
reference to the accompanying drawings.
First Embodiment
(Basic Configuration)
[0027] As shown in FIG. 1, a valve opening/closing timing control
device includes an outer rotor 1 serving as a driving side
rotational member and synchronously rotatable with a crankshaft
(not shown) of an engine (an internal combustion engine), an inner
rotor 2 serving as a driven side rotational member and coaxially
and synchronously rotatable with a camshaft 3 which opens and
closes an intake valve or an exhaust valve in a combustion chamber
of the engine, and a fluid control valve mechanism V.
[0028] The valve opening/closing timing control device includes a
configuration in which the inner rotor 2 (driven side rotational
member) is inserted in the outer rotor 1 (driving side rotational
member). Consequently, the outer rotor 1 and the inner rotor 2 can
be relatively rotated around a core X of a rotational shaft in the
range of a desired relative rotational phase. A fluid pressure
chamber is formed between the outer rotor 1 and the inner rotor 2,
and as shown in FIG. 2, the fluid pressure chamber is partitioned
into a retarded angle chamber 11 and an advanced angle chamber 12
by a vane 5 serving as a partitioning portion supported on an outer
circumference of the inner rotor 2.
[0029] The vane 5 is inserted into a vane groove formed in the
outer circumference of the inner rotor 2, and is biased in a
protruding direction by a leaf spring or the like. Consequently,
irrespective of a relative phase of the outer rotor 1 and the inner
rotor 2, an outer end portion of the vane 5 is always slidably held
on an inner surface of the outer rotor in the fluid pressure
chamber.
[0030] The camshaft 3 is coaxially arranged with the core X of the
rotational shaft. The camshaft 3 is connected to the inner rotor 2
by means of a connecting bolt 4. A front plate 6 is placed on one
surface of the outer rotor 1, and a rear plate 7 is placed on the
other surface of the outer rotor 1. The front plate 6 and the rear
plate 7 are fixed to the outer rotor 1 by means of a plurality of
fixing bolts 8. The inner rotor 2 is interposed between the front
plate 6 and the rear plate 7.
[0031] A timing sprocket 7S is integrally installed on the outer
periphery of the rear plate 7. Between the timing sprocket 7S and a
gear attached to the crankshaft of the engine, there is provided a
power transmission member (not shown) such as a timing chain or a
timing belt.
[0032] In the configuration, upon start-up of the engine, a
rotational driving force of the crankshaft is transmitted to the
timing sprocket 7S through the power transmission member, and the
outer rotor 1 rotates in a rotational direction T shown in FIG. 2
or the like. As the inner rotor 2 rotates in the same direction as
the rotational direction T in conjunction with the rotation, the
camshaft 3 rotates, and the intake valve or the exhaust valve of
the engine is opened or closed by the driving rotation of a cam
(not shown) provided on the camshaft 3.
[0033] When the engine operates, if the advanced angle chamber 12
is supplied with operating oil, the volume of the advanced angle
chamber 12 is enlarged by the pressure acting on the vane 5, and
thus the inner rotor 2 is moved in a direction denoted by an arrow
Ti with respect to the outer rotor 1. Consequently, the relative
rotational phase of the outer rotor 1 and the inner rotor 2 is
shifted in an advanced angle direction. In contrast, if the
retarded angle chamber 11 is supplied with the operating oil, the
volume of the retarded angle chamber 11 is enlarged by the pressure
acting on the vane 5 in an adverse direction, and thus the inner
rotor 2 is moved in a direction denoted by an arrow T2 with respect
to the outer rotor 1. Consequently, the relative rotational phase
of the outer rotor 1 and the inner rotor 2 is shifted in a retarded
angle direction. The opening and closing timing of the intake vale
or exhaust valve is controlled by changing a rotational phase of
the camshaft 3 with respect to the rotational phase of the
crankshaft.
[0034] Engine oil is used as the operating oil, and the valve
opening/closing timing control device includes a maintenance
mechanism M to maintain the relative rotational phase between the
outer rotor 1 and the inner rotor 2 at a start-up optimum phase
(referred to as an intermediate phase, and one example of the
predetermined phase) suitable for the start-up of the engine. The
maintenance mechanism M maintains the outer rotor 1 and the inner
rotor 2 at the set relative rotational phase in circumstances in
which the pressure of the operating oil is very low immediately
after the start-up of the engine. Therefore, the rotational phase
of the camshaft 3 with respect to the rotational phase of the
crankshaft is maintained at the start-up optimum phase, thereby
providing the stable start-up of the engine.
[0035] A general maintenance mechanism in the valve opening/closing
timing control device of a related art is constituted of a lock
groove formed in the inner rotor, and a lock pin supported on the
outer rotor to be extendable and retractable to each of the lock
groove.
[0036] However, the maintenance mechanism M disclosed here includes
two spiral springs S1 and S2 applying the biasing force between the
outer rotor 1 (driving side rotational member) and the inner rotor
2 (driven side rotational member) in mutually reverse directions.
The first spiral spring S1 biases the relative phase toward the
advanced angle side, and the second spiral spring S2 biases the
relative phase toward the retarded angle side. The two spiral
springs S1 and S2 are kept in a concave portion 6a formed in the
front plate 6, and a disc spacer 15 is interposed between the
spiral springs S1 and S2. The concave portion 6a is covered by a
disc cover 9. The operation of the spiral springs S1 and S2 will be
described in detail.
[0037] As shown in FIGS. 1 and 2, the inner rotor 2 is provided
with a retarded angle chamber side passage 11a through which the
operating oil is supplied or discharged to or from the plurality of
retarded angle chambers 11, and an advanced angle chamber side
passage 12a through which the operating oil is supplied or
discharged to or from the plurality of advanced angle chambers 12
in a penetrating manner. Since the lock pin is not provided as the
maintenance mechanism, there is no lock release passage or the like
for pushing the lock pin out from the lock groove.
[0038] As shown in FIGS. 1 and 2, the valve opening/closing timing
control device includes a bush 18 fitted to the outer circumference
of the camshaft 3 so as to relatively rotate with respect to the
camshaft 3. There is an oil passage system to supply sequentially
the operating oil to an internal oil passage 3a of the camshaft 3
and an internal oil passage 2a of the inner rotor 2 from a supply
oil passage 18a of the bush 18. The operating oil supplied from a
hydraulic pump P to the supply oil passage 18a is supplied to a
cylindrical space 2S of the inner rotor 2 by the oil passage
system.
[0039] Further, the operating oil supplied to the cylindrical space
2S is supplied to the retarded angle chamber side passage 11a and
the advanced angle chamber side passage 12a described above through
the fluid control valve mechanism V which is relatively rotatably
supported with respect to the outer rotor 1 and the inner rotor 2,
and is discharged from the retarded angle chamber side passage 11a
and the advanced angle chamber side passage 12a.
(Fluid Control Valve Mechanism)
[0040] The fluid control valve mechanism V includes, as shown in
FIG. 1, a housing 28 integrally constituted of an operating oil
control portion Va having a spool valve 22, and an operating oil
supply/discharge portion Vb of a cylindrical shape to perform the
distribution of the operating oil. The spool valve 22 is slid by an
electromagnetic solenoid 21 disposed on an upper end portion of the
operating oil control portion Va in an upper and lower portion on
the figure. The operating oil supply/discharge portion Vb is
rotatably inserted in the cylindrical space 2S of the inner rotor
2.
[0041] A main oil passage 23 penetrates into the center portion of
the operating oil supply/discharge portion Vb to receive the
operating oil from the above-described inner oil passage 2a, and a
check valve C is provided in the main oil passage 23 to block flow
of the fluid toward the cylindrical space 2S. The spool valve 22
has a bottomed cylindrical shape.
[0042] The housing 28 is fixed to a front cover or the like of the
engine, and the inner rotor 2 is rotatably supported by the
operating oil supply/discharge part Vb.
[0043] In the outer circumference of the operating oil
supply/discharge part Vb, two ports 24 and 25 are formed in a
groove, in which the distribution of the operating oil is
controlled by the spool valve 22. An oil seal 27 is formed on the
outer circumference of the operating oil supply/discharge portion
Vb to suppress leakage of the operating oil from the first port 24
and the second port 25. The first port 24 is always in
communication with the retarded angle chamber side passage 11a, and
the second port 25 is always in communication with the advanced
angle chamber side passage 12a.
[0044] A compression spring 29 is installed between the spool valve
22 and the bottom surface of the housing 28 to bias the spool valve
22 in an upward direction on the figure. If the solenoid 21 is
energized in the state of FIG. 1, an operation rod 30 protruding
downward from the solenoid 21 moves the spool valve 22 to a
downward position. If the energization is stopped, the operation
rod 30 is retracted toward the solenoid 21 side, and the spool
valve 22 is returned to an upward position shown in FIG. 1 by the
biasing force of the compression spring 29 while following up with
the movement of the rod 22.
[0045] In the outer circumferential surface of the spool valve 22,
ring-shaped discharge grooves 22a and 22b and a ring-shaped supply
groove 22c are formed. The discharge grooves 22a and 22b are
respectively provided with through-holes 23a and 23b penetrating an
inner hollow portion.
[0046] A position relationship between the discharge grooves 22a
and the 22b and the supply groove 22c is set in such a manner that
the supply groove 22c is in communication with the main oil passage
23 and the advanced angle chamber communication hole 12a and the
discharge groove 22b is in communication with the retarded angle
chamber side passage 11a, as shown in FIG. 1, when the solenoid 21
is deenergized. Further, it is set in such a manner that the supply
groove 22c is in communication with the main oil passage 23 and the
retarded angle chamber side passage 11a and the discharge groove
22a is in communication with the advanced angle chamber side
passage 12a, when the solenoid 21 is energized.
[0047] In the valve opening/closing timing control device, a gap is
formed between the inner rotor 2 and the front plate 6 and between
the inner rotor 2 and the rear plate 7, through which the operating
oil slightly leaks. The operating oil slightly leaks through the
other movable portion. The leaked operating oil is collected by an
oil pan 36.
(Operation of Valve Opening/Closing Timing Control Device)
[0048] As shown in FIG. 1, in the case where the relative
rotational phase is displaced in the advanced angle direction T1,
the solenoid 21 is in a deenergized state during the operation of
the oil pressure pump P. Then, the spool valve 22 is placed at the
upward position of the solenoid 21 together with the rod 30 of the
solenoid 21 by the biasing force of the compression spring 29. The
operating oil supplied to the main oil passage 23 of the camshaft 8
from the hydraulic pump P is fed to each advanced angle chamber 12
through the cylindrical space 2S, the main oil passage 23, the
supply groove 22c, the advanced angle chamber side passage 12a and
the second port 25, as shown in FIG. 1. The vane 5 is moved in the
advanced angle direction T1 by the feeding, and the operating oil
of each retarded angle chamber 11 is discharged. The operating oil
discharged from the retarded angle chamber 11 is discharged to the
oil pan 36 through the first port 24, the retarded angle chamber
side passage 11a, the discharge groove 22b and a drain passage
35.
[0049] On the other hand, in the case where the relative rotational
phase is displaced in the retarded angle direction T2, the solenoid
21 is energized during the operation of the oil pressure pump P.
The spool valve 22 is pushed into the rod 22 of the solenoid 21 and
then is positioned at the downward position. The operating oil
supplied to the main oil passage 23 of the camshaft 8 from the
fluid pump P is fed to each retarded angle chamber 11 through the
cylindrical space 2S, the main oil passage 23, the supply groove
22c, the retarded angle chamber side passage 11a and the first port
24. The vane 5 is moved in the retarded angle direction T2 by the
feeding, so that the operating oil of each advanced angle chamber
12 is discharged. The operating oil discharged from the advanced
angle chamber 12 is discharged to the oil pan 36 through the second
port 25, the advanced angle chamber side passage 12a, the discharge
groove 22a and the drain passage 35.
(Schematic Description of Control System)
[0050] Although not shown in the figures, the control system of the
valve opening/closing timing control device includes a crank angle
sensor detecting the rotational angle of the crankshaft of the
engine, a camshaft angle sensor detecting the rotational angle of
the camshaft 3, and an ECU (not shown) controlling the fluid
control valve mechanism V.
[0051] The ECU is provided with a signal system acquiring ON/OFF
information of an ignition key, information from an oil temperature
sensor detecting the temperature of the engine oil, or the like,
and control information of the optimum relative rotational phase
according to the driving state of the engine is stored in a
nonvolatile memory.
[0052] The ECU detects the relative phase of the outer rotor 1 and
the inner rotor 2 from the detected result of the above-described
crank angle sensor and camshaft angle sensor. The distribution of
the operating oil to each of the retarded angle chamber 11 and the
advanced angle chamber 12 is performed by operating the fluid
control valve mechanism V based on the information of the relative
phase and the information of the driving state (e.g., revolutions
of engine, temperature of cooling water or the like), thereby
controlling the relative rotational phase of the outer rotor 1 and
the inner rotor 2. Consequently, the phase control is achieved
between the most retarded angle phase (relative rotational phase in
which the volume of the retarded angle chamber 11 is maximized) and
the most advanced angle phase (relative rotational phase in which
the volume of the advanced angle chamber 12 is maximized).
[0053] If the operation is performed to stop the engine, the ECU
stops the distribution of the operating oil to the retarded angle
chamber 11 and the advanced angle chamber 12 by the fluid control
valve mechanism V, so that the vane 5 is not applied with the
operating oil of any direction. Consequently, the engine stops in
the state in which the relative phase of the outer rotor 1 and the
inner rotor 2 is displaced at the start-up optimum phase suitable
for next start-up by the above-described biasing operation of the
spiral springs S1 and S2. When the engine starts up after the stop,
the engine starts up reliably.
[0054] In this instance, when the inner rotor 2 is positioned in
the area in the retarded angle side than the start-up optimum phase
with respect to the outer rotor 1, the above-described spiral
springs S1 and S2 have a function of applying the biasing force to
the inner rotor 2 in a direction of the start-up optimum phase
against the reaction force received from the valve spring of the
intake valve or exhaust valve in cooperation with each other. More
specifically, the biasing force of the spiral spring S1 biasing the
relative phase to the advanced angle side is set to be higher than
that of the spiral spring S2 biasing the relative phase to the
retarded angle side. Consequently, a problem that the relative
phase of the inner rotor 2 integrally rotating with the camshaft 3
tends to be retarded with respect to the rotation of the outer
rotor 1 due to the reaction force received from the valve spring of
the intake valve or exhaust valve, or the tendency that the
relative phase is maintained at the retarded angle side rather than
the start-up optimum phase when the operating oil is discharged
from the retarded angle chamber 11 and the advanced angle chamber
12 are suppressed.
[0055] After the start-up of the engine, the ECU performs the
distribution of the operating oil to each of the retarded angle
chamber 11 and the advanced angle chamber 12 by the fluid control
valve mechanism V to change the relative phase of the outer rotor 1
and the inner rotor 2, so that the control of the opening and
closing timing of the intake valve and the exhaust valve is
performed by the ECU.
[0056] In a case where the engine is in the stop state, since
excessive load is applied to the engine, the inner rotor 2 may
reach the most retarded angle phase with respect to the outer rotor
1. When the engine starts up in this situation, in order to perform
stable engine starting, the ECU controls the phase of the inner
rotor 2 with respect to the outer rotor 1 to move at the start-up
optimum phase early.
[0057] As a detailed control mode, the fluid control valve
mechanism V discharges the operating oil from the retarded angle
chamber 11 and supplies the operating oil to advanced angle chamber
12 by the control of the ECU, the inner rotor 2 with respect to the
outer rotor 1 is moved in the direction of the start-up optimum
phase. In this instance, the rotational phase of the most retarded
angle phase, in which the inner rotor 2 is disposed at the most
retarded angle side, is referred to as the most retarded angle
phase.
[0058] However, according to the above-described control, in a case
in which the engine starts up in the state in which the inner rotor
2 is at the most retarded angle phase, the time is needed until the
relative rotational phase reaches the start-up optimum phase, so
that the start-up of the engine is not smoothly performed. In
particular, the operating oil is cold at the time of stopping the
engine in cold climates, the viscosity of the operating oil is
high, and thus the distribution of the operating oil to each of the
retarded angle chamber 11 and the advanced angle chamber 12 is not
smoothly performed. For this reason, the start-up of the engine is
not smoothly performed. In order to address the above problem, it
is aimed to shorten the time required to reach the start-up optimum
phase by assisting the relative movement of the outer rotor 1 and
the inner rotor 2 in the direction of the start-up optimum phase by
means of the above-described difference in the intensity of the
spiral springs S1 and S2.
(Spiral Spring)
[0059] As shown in FIGS. 3A and 3B to FIG. 8, the first spiral
spring S1 operates to bias the rotational phase of the inner rotor
2 with respect to the outer rotor 1 in the direction of the
start-up optimum phase in a retarded angle region A from the most
retarded angle phase to the start-up optimum phase. In contrast,
the second spiral spring S2 operates to bias the rotational phase
of the inner rotor 2 with respect to the outer rotor 1 in the
direction of the start-up optimum phase in an advanced angle region
B from the most advanced angle phase to the start-up optimum
phase.
[0060] As shown in FIG. 8, since the spiral springs S1 and S2 are
formed in a spiral shape from a strap of spring material, the thick
(dimension of the rotational shaft in the direction of the core X)
can be thinned as compared with one including a coil portion such
as a torsion spring. As shown in FIG. 1, in a case where two spiral
springs S1 and S2 are installed, since a large space is not
required in the direction of the core X of the rotational shaft, it
is possible to downsize the valve opening/closing timing control
device.
[0061] As shown in FIGS. 3A and 3B, each of the spiral springs S1
and S2 has a spiral spring body 30 in a spiral shape. An end
portion thereof in an inner diameter side is provided with an inner
engaging portion 31 which is formed by bending the end portion in a
radially inward direction and is engaged to the inner rotor 2. An
end portion thereof in an outer diameter side is provided with an
outer engaging portion 32 which is formed by bending the end
portion in a radially outward direction and is fixed to the outer
rotor 1.
[0062] The outer circumference of an axial portion 10 of the inner
rotor 2 is provided on one portion thereof with an engaging concave
portion 10G which may be engaged to the inner engaging portion 31,
so as to correspond to the shape of the spiral springs S1 and S2.
The inner surface of the front plate 6 connected to the outer rotor
1 is provided on one portion thereof with an engaging concave
portion 6T which may be engaged to the outer engaging portion
32.
[0063] When the spiral springs S1 and S2 are set, first, after the
engaging concave portion 6T of the outer rotor 1 is engaged and
fixed to the outer engaging portion 32, the inner engaging portion
31 is turned by predetermined turns against the biasing force of
the spiral springs S1 and S2 which tend to be returned in a
straight direction, in other words, in a direction of the spring
body 30 which is curled in an inner diameter direction around the
axis X, the inner engaging portion 31 is engaged and fixed to the
engaging concave portion 10G. The rotation operating direction of
the inner engaging portion 31 at the time of performing the setting
corresponds to a counterclockwise direction in the first spring S1,
and corresponds to a clockwise direction in the second spiral
spring S2, in FIG. 2.
[0064] By setting the springs in the above manner, both ends of the
spiral springs S1 and S2 are reliably fixed to each of the outer
rotor 1 and the inner rotor 2 so as to prevent the relative
movement therebetween, thereby achieving the configuration in which
the inner engaging portion 31 of the first spiral spring S1 biases
the inner rotor 2 toward the advanced angle side (clockwise
direction in FIG. 2) and the inner engaging portion 31 of the
second spiral spring S2 biases the inner rotor 2 toward the
retarded angle side (counterclockwise direction in FIG. 2).
[0065] In this instance, only one of the two spiral springs S1 and
S2 may be disposed in the concave portion 6a formed in the front
plate 6, and the other may be disposed in the concave portion
formed in the rear plate 7. In this instance, the disc spacer 15 is
not required.
(Operation Control)
[0066] As described above, since the distribution of the operating
oil to each of the retarded angle chamber 11 and advanced angle
chamber 12 is stopped at the general start-up of the engine, as
shown in FIG. 2 and FIGS. 3A and 3B, the relative phase of the
outer rotor 1 and the inner rotor 2 is maintained at the start-up
optimum phase between the most retarded angle phase and the most
advanced angle phase by the biasing operation of the spiral springs
S1 and S2. Consequently, the engine can start up reliably. If the
start-up of the engine is instructed by ON operation of the
ignition key, cranking is executed by a cell motor, and the engine
starts up. The hydraulic pump P rotates, so that the operating oil
can be supplied to the retarded angle chamber 11 and the advanced
angle chamber 12.
[0067] After the start-up of the engine, since the operating oil is
generally supplied to the retarded angle chamber 11 by the fluid
control valve mechanism V in accordance with the control of the
ECU, the relative rotational phase is displaced to the intermediate
control phase slightly closer to the retarded angle phase side
rather than the start-up optimum phase. The intermediate control
phase is a phase suitable for improvement of the emission or
torque-up at cold temperatures, and this phase is generally
maintained during warm air driving. In this instance, FIG. 4 and
FIGS. 5A and 5B show the state of the most retarded angle phase
exceeding the intermediate control phase.
[0068] Since the displacement operation from the start-up optimum
phase to the retarded angle phase side such as the intermediate
control phase by the supply of the operating oil to the retarded
angle chamber 11 is followed by the relative rotation operation of
the inner rotor 2 in a counterclockwise direction in FIG. 4 and
FIGS. 5A and 5B, it is performed against the biasing force of the
first spiral spring S1, that is, with the further pulling-up of the
first spiral spring S1. Meanwhile, since the second spiral spring
S2 is set in a state in which it is sufficiently pulled up, the
second spiral spring S2 is simply loosen in the displacement from
the start-up optimum phase to the retarded angle phase side, as
compared with the state in the start-up optimum phase. Therefore,
it does not exert the biasing force to move the relative rotational
phase in the advanced angle direction. If the period of the warm
air driving has been passed, the ECU transits to a general driving
control.
[0069] When the displacement operation is performed to the advanced
angle side rather than the start-up optimum phase in the general
driving control, it is followed by the relative rotation operation
of the inner rotor 2 in a clockwise direction in FIG. 6 and FIGS.
7A and 7B, it is performed against the biasing force of the second
spiral spring S2, that is, with the further tightening of the
second spiral spring S2. Meanwhile, since the first spiral spring
S1 is set in a state in which it is sufficiently pulled up, the
first spiral spring is simply loosen in the displacement from the
start-up optimum phase to the advanced angle phase side, as
compared with the state in the start-up optimum phase. Therefore,
it does not exert the biasing force to move the relative rotational
phase in the retarded angle direction. In this instance, FIG. 6 and
FIGS. 7A and 7B show the state of the most advanced angle
phase.
Second Embodiment
[0070] A second embodiment disclosed here will now be described
with reference to the accompanying drawings.
[0071] The second embodiment includes two spiral springs S1 and S2
to bias a biasing force in a mutually reverse direction, as the
maintenance mechanism M for maintaining the relative rotational
phase of the outer rotor 1 and the inner rotor 2 at the start-up
optimum phase suitable for the start-up of the engine, similar to
the first embodiment.
[0072] The first feature of the configuration according to the
second embodiment is that the width of the engaging concave portion
10G of the inner rotor 2 in a circumferential direction is
sufficiently larger than the thickness of the inner engaging
portion 31 of the spiral springs S1 and S2, as shown in FIGS. 9A to
12. With the above configuration, the respective inner engaging
portions 31 engaged to the engaging concave portion 10G are movable
along the circumferential direction in the engaging concave portion
10G.
[0073] The second feature of the configuration according to the
second embodiment is that the front plate 6 is provided with first
restriction piece 33A in a standing manner which can abut against
the inner engaging portion 31 of the first spiral spring S1, and
the front plate 6 is provided with second restriction piece 33B in
a standing manner which can abut against the inner engaging portion
31 of the second spiral spring S2. The first restriction piece 33A
restricts the displacement of the inner engaging portion 31 of the
first spiral spring S1 in the direction of the advanced angle
region B, and the second restriction piece 33B restricts the
displacement of the inner engaging portion 31 of the second spiral
spring S2 in the direction of the retarded angle region A.
[0074] As a result, as shown in FIG. 10A, the first spiral spring
S1 operates to bias the rotational phase of the inner rotor 2 with
respect to the outer rotor 1 in the direction of the start-up
optimum phase in the retarded angle region A from the most retarded
angle phase to the first predetermined phase (corresponding to the
start-up optimum phase) defined by the first restriction piece 33A.
In contrast, as shown in FIG. 11B, the second spiral spring S2
operates to bias the rotational phase of the inner rotor 2 with
respect to the outer rotor 1 in the direction of the start-up
optimum phase in the advanced angle region B from the most advanced
angle phase to the second predetermined phase (corresponding to the
start-up optimum phase) defined by the second restriction piece
33B.
[0075] As shown in FIG. 10B, in the retarded angle region A from
the most retarded angle phase to the start-up optimum phase, since
the inner engaging portion 31 of the second spiral spring S2 is
engaged by the second restriction piece 33B, it does not move
relatively in the engaging concave portion 10G with the wide width
in the advanced angle direction to act on the inner rotor 2 at the
earliest. For this reason, only the biasing force of the first
spiral spring S1 acts on the rotational phase, and the biasing
force does not act on the rotational phase from the second spiral
spring S2.
[0076] In contrast, as shown in FIG. 11A, in the advanced angle
region B from the most advanced angle phase to the start-up optimum
phase, since the inner engaging portion 31 of the first spiral
spring S1 is engaged by the first restriction piece 33A, it does
not move relatively in the engaging concave portion 10G with the
wide width in the retarded angle direction to act on the inner
rotor 2 at the earliest. For this reason, only the biasing force of
the second spiral spring S2 acts on the rotational phase, and the
biasing force does not act on the rotational phase from the first
spiral spring S1.
[0077] As a result, since the biasing operation position to the
inner rotor 2 by the inner engaging portion 31 of the respective
spiral springs S1 and S2 is limited to each position of the first
and second restriction pieces 33A and 33B, if the distribution of
the operating oil to each of the retarded angle chamber 11 and the
advanced angle chamber 12 is stopped, as shown in FIGS. 9A and 9B,
in a case where the balance of the biasing force of the respective
spiral springs S1 and S2 is lost from an original state due to
long-termed use, the rotational phase is not deviated by the
collapse in the balance, and can be maintained at the start-up
optimum phase with high accuracy.
Third Embodiment
[0078] A third embodiment employs not the spiral spring, but two
torsion springs S1 and S2 as a biasing member for maintaining the
relative phase at the start-up optimum phase, as shown in FIG. 13
and FIGS. 14A and 14B. The first torsion spring S1 biasing the
relative phase toward the advanced angle side is received in the
concave portion 6a of the front plate 6, while the second torsion
spring S2 biasing the relative phase toward the retarded angle side
is received in a concave portion 7a of the rear plate 7.
[0079] FIGS. 14A and 14B show the state of the respective torsion
springs S1 and S2 at the start-up optimum phase.
[0080] The outer engaging portions 32 of the torsion springs S1 and
S2 are engaged to the engaging concave portion 6T in a relatively
non-movable manner in the inner surface of the front plate 6 which
is connected to the outer rotor 1. However, the inner engaging
portions 31 of the torsion springs S1 and S2 are engaged to the
engaging concave portion 10G with a wide width in a relatively
movable manner, the width of the engaging concave portion being cut
sufficiently rather than an outer diameter of the inner engaging
portion 31.
[0081] The restriction pieces 33A and 33B engaging to the inner
engaging portions 31 of the torsion springs S1 and S2 protrude from
the bottom portion of the front plate 6.
[0082] The same working effect as the second embodiment is achieved
by the engaging concave portion 10G with the wide width and the
restriction pieces 33A and 33B.
[0083] As will be understood from FIG. 14A, in the advanced angle
region B from the most advanced angle phase to the start-up optimum
phase, since the inner engaging portion 31 of the first torsion
spring S1 is engaged by the first restriction piece 33A, it does
not act on the inner rotor 2. For this reason, only the biasing
force of the second torsion spring S2 acts on the rotational phase,
and the biasing force does not act on the rotational phase from the
first torsion spring S1.
[0084] In contrast, as will be understood from FIG. 14B, in the
retarded angle region A from the most retarded angle phase to the
start-up optimum phase, since the inner engaging portion 31 of the
second torsion spring S2 is engaged by the second restriction piece
33B, it does not act on the inner rotor 2. For this reason, only
the biasing force of the first torsion spring S1 acts on the
rotational phase, and the biasing force does not act on the
rotational phase from the second torsion spring S2.
[0085] As a result, since the biasing operation position to the
inner rotor 2 by the inner engaging portion 31 of the respective
torsion springs S1 and S2 is limited to each position of the first
and second restriction pieces 33A and 33B, if the distribution of
the operating oil to each of the retarded angle chamber 11 and the
advanced angle chamber 12 is stopped, in a case where the balance
of the biasing force of the respective torsion springs S1 and S2 is
lost from an original state due to long-term use, the rotational
phase is not deviated by the collapse in the balance, and can be
maintained at the start-up optimum phase with high accuracy. The
position of the first restriction piece 33A corresponds to the
first predetermined phase, and the position of the second
restriction piece 33B corresponds to the second predetermined
phase.
Fourth Embodiment
[0086] A fourth embodiment employs single torsion spring S having
an inner engaging portion 31 which is engaged to the engaging
concave portion 10G of the inner rotor 2 and an outer engaging
portion 32 which is engaged to the engaging concave portion 6T of
the outer rotor 1, as a biasing member for maintaining the relative
phase at the start-up optimum phase, as shown in FIG. 15.
[0087] In this embodiment, if the distribution of the operating oil
to each of the retarded angle chamber 11 and the advanced angle
chamber 12 is stopped, the relative phase is displaced at the
start-up optimum phase by the biasing force of the torsion spring
S, and is maintained at this phase. The displacement operation from
the start-up optimum phase to the retarded angle side by the
operating oil is performed, with being accompanied by deformation
in which the inner engaging portion 31 of the torsion spring S
relatively rotates in a counterclockwise direction with respect to
the outer engaging portion 32, when seen at plane view in FIG. 15,
that is, the diameter of the torsion spring S is decreased. In
contrast, the displacement operation from the start-up optimum
phase to the advanced angle side is performed, being accompanied by
deformation in which the inner engaging portion 31 of the torsion
spring S relatively rotates in a clockwise direction with respect
to the outer engaging portion 32, when seen at plane view in FIG.
15, that is, the diameter of the torsion spring S is increased.
Fifth Embodiment
[0088] A fifth embodiment employs the engaging concave portion 10
of the inner rotor 2 extended long in a circumferential direction
and single torsion spring S fitted to the cylindrical operating oil
supply/discharge portion Vb, as a biasing member for maintaining
the relative phase at the start-up optimum phase. Both ends 31a and
31b of the torsion spring S are extended outwardly in a radial
direction, and the torsion spring S is fitted into the engaging
concave portion 10 in a state in which both ends 31a and 31b are
close to each other against the biasing force of the torsion spring
S.
[0089] The front plate 6 is provided with a pair of restriction
pieces 34A and 34B in a standing manner which abut against or are
adjacent to the outside of the torsion spring S in the vicinity of
both ends 31a and 31b. In a state in which the distribution of the
operating oil to each of the retarded angle chamber 11 and the
advanced angle chamber 12 is stopped, as shown in FIG. 16A, both
ends 31a and 31b of the torsion spring S are simultaneously pushed
by both ends 10a and 10b of the engaging concave portion 10 and the
pair of the restriction pieces 34A and 34B, thereby biasing the
relative phase at the start-up optimum phase.
[0090] If the relative phase is displaced toward the retarded angle
side by the operation of the operating oil, as shown in FIG. 16B,
the displacement operation is performed by pushing the other end
portion 31a of the torsion spring S in a counterclockwise direction
with one end surface 10a of the engaging concave portion 10G of the
inner rotor 2, with one end portion 31b of the torsion spring S
being pushed by the restriction piece 34B.
[0091] The embodiments disclosed here can be used in the whole
valve opening/closing timing control devices capable of setting the
opening and closing timing of anyone of an intake valve and an
exhaust valve of an engine.
[0092] According to a first aspect of this disclosure, a valve
opening/closing timing control device includes a driving side
rotational member synchronously rotatable with a crankshaft of an
internal combustion engine, a driven side rotational member
arranged coaxially with the driving side rotational member and
synchronously rotatable with a camshaft that opens and closes any
one of intake and exhaust valves of the internal combustion engine,
a phase converting mechanism displacing a relative phase between
the driving side rotational member and the driven side rotational
member toward an advanced angle phase side or a retarded angle
phase side by distributing an operating fluid to each of two kinds
of pressure chambers, the volume of which is complementarily varied
by a movable partition, and a biasing member biasing the relative
phase toward a predetermined phase suitable for a start-up of the
internal combustion engine except for a most advanced angle phase
and a most retarded angle phase.
[0093] The valve opening/closing timing control device according to
the first aspect of this disclosure does not require a lock
mechanism constituted of a lock groove formed on one rotational
member and a lock pin supported by the other rotational member, but
includes the biasing member biasing the relative phase toward a
predetermined phase (start-up optimum phase) suitable for a
start-up of the internal combustion engine except for a most
advanced angle phase and a most retarded angle phase. Consequently,
in a state in which it is free of the force of operating oil, the
relative phase is shifted to the start-up optimum phase by the
movement of the biasing member. Accordingly, since there is no
problem in that the movement of the lock pin is interfered with by
foreign substances contained in the oil, the maintenance of the
relative phase in the start-up optimum phase is carried out
reliably by the biasing member.
[0094] Further, since the lock mechanism is not constituted of a
lock groove formed on one rotational member and a lock pin
supported by the other rotational member, but constituted of a
biasing member interposed between the driving side rotational
member and the driven side rotational member, it is mechanistically
simple, and thus the valve opening/closing timing control device
which is not susceptible to failure is obtained. In addition, it is
possible to downsize the valve opening/closing timing control
device.
[0095] Furthermore, since it does not require a lock mechanism with
a lock pin which alternatively performs fitting and leaving to each
of a lock groove, noise is not generated by the lock mechanism when
the internal combustion engine starts up.
[0096] According to a second aspect of this disclosure, the biasing
member includes a first biasing member to bias the relative phase
in a direction of the advanced angle phase and a second biasing
member to bias the relative phase in a direction of the retarded
angle phase, and the biasing member further includes a first
restricting portion to define the biasing force of the first
biasing member between the predetermined phase and the most
retarded angle phase, and a second restricting portion to define
the biasing force of the second biasing member between the
predetermined phase and the most advanced angle phase.
[0097] The biasing member biasing the relative phase toward the
predetermined phase in a range from the most advanced angle phase
side to the most retarded angle phase side may be constituted by
one torsion spring (biasing member) to bias the relative phase
toward the predetermined phase under circumstances in which an
external force does not act. However, since the biasing force of
the biasing member is most small near the predetermined phase, it
is difficult to maintain the relative phase reliably at the
predetermined phase. Further, as it is deviated from the
predetermined phase to the most advanced angle phase side or the
most retarded angle phase side, a restoring force of the biasing
member is increased. As a result, high oil pressure is needed to
displace the relative phase against the biasing force of the
biasing member, which tends to increase energy loss.
[0098] However, as the configuration, if it is constituted of two
biasing members, in which a biasing direction thereof is opposite
to each other, and the relative phase is biased to the
predetermined phase in cooperation with an acting force from two
biasing members, the relative phase can be maintained reliably at
the predetermined phase, for example, as compared with the above
configuration in which one torsion spring (biasing member) is
installed.
[0099] In the configuration, when the relative phase is operated
from the predetermined phase to the retarded angle phase side or
the advanced angle phase side by operation of the oil pressure or
the like, for example, when the relative phase is operated toward
the retarded angle phase side, only the biasing force of one
biasing member acts in a state in which the biasing force of the
second biasing member is defined between the predetermined phase
and the most advanced angle phase by the second restriction
portion. Therefore, the relative phase can be displaced by
relatively small oil pressure.
[0100] In addition, in the configuration, according to the
respective restriction portions, the biasing force by the first
biasing member is defined between the predetermined phase and the
most retarded angle phase and the biasing force by the second
biasing member is defined between the predetermined phase and the
most advanced angle phase. Therefore, in a state in which there is
no oil pressure or the like for performing the displacement
operation of the relative phase, the predetermined phase is
achieved in a state in which the biasing force by the first biasing
member toward the advanced angle phase rather than the
predetermined phase is restricted by the first restriction portion,
and the biasing force by the second biasing member toward the
retarded angle phase rather than the predetermined phase is
restricted by the second restriction portion. As a result, in a
case where two biasing forces are not equal to each other through
error in manufacturing precision of the biasing members or the
like, the relative phase can be easily controlled at the original
desired phase without deviating to the retarded phase side or the
advanced angle phase side through the error.
[0101] According to a third aspect of this disclosure, the biasing
member has the biasing force against a displacing force acting on
the driven side rotational member based on torque fluctuation of
the camshaft.
[0102] With the configuration, since the biasing force of the
biasing member tends to offset the displacing force acting on the
driven side rotational member based on the torque fluctuation of
the camshaft, it is possible to increase the maintaining accuracy
of the relative phase by the biasing member in the predetermined
phase, and control accuracy of the relative phase by oil pressure
is enhanced.
[0103] According to a fourth aspect of this disclosure, the biasing
member is a spring placed between the driving side rotational
member and the driven side rotational member.
[0104] With the configuration, since the aspect of this disclosure
can be implemented by the biasing member of a simple configuration
in which a spring such as a torsion spring or a spiral spring is
disposed between the driving side rotational member and the driven
side rotational member which are placed adjacent to each other, an
assembling operation of the valve opening/closing timing control
device is easily performed, and miniaturization can be easily
performed.
[0105] According to a fifth aspect of this disclosure, a valve
opening/closing timing control device includes a driving side
rotational member synchronously rotatable with a crankshaft of an
internal combustion engine, a driven side rotational member
arranged coaxially with the driving side rotational member and
synchronously rotatable with a camshaft that opens and closes any
one of intake and exhaust valves of the internal combustion engine,
a retarded angle chamber and an advanced angle chamber formed by
the driving side rotational member and the driven side rotational
member, in which the retarded angle chamber moves a relative phase
of the driven side rotational member to the driving side rotational
member in a retarded angle direction as a volume thereof is
enlarged, and the advanced angle chamber moves the relative phase
in an advanced angle direction as a volume thereof is enlarged, and
a biasing member biasing the relative phase toward a predetermined
phase except for a most advanced angle phase and a most retarded
angle phase.
[0106] That is, the valve opening/closing timing control device
according to the fifth aspect of this disclosure does not require a
lock mechanism constituted of a lock groove formed on one
rotational member and a lock pin supported by the other rotational
member, but includes the biasing member biasing the relative phase
toward a predetermined phase except for the most advanced angle
phase and the most retarded angle phase. Consequently, in a state
in which it is free of the force of the operating oil, the relative
phase is shifted to the predetermined phase by the movement of the
biasing member. Accordingly, since there is no problem in that the
movement of the lock pin is interfered with by foreign substances
contained in the oil, the maintenance of the relative phase in the
predetermined phase (e.g., start-up optimum phase) is carried out
reliably by the biasing member.
[0107] According to a sixth aspect of this disclosure, the biasing
member includes a first biasing member to bias the relative phase
to a first predetermined phase which is positioned in a direction
of the advanced angle phase rather than the most retarded angle
phase, and a second biasing member to bias the relative phase to a
second predetermined phase which is positioned in a direction of
the retarded angle phase rather than the most advanced angle phase.
The first biasing member biases the relative phase from the most
retarded angle phase to the first predetermined phase and does not
bias the relative phase from the first predetermined phase to the
most advanced angle phase. The second biasing member biases the
relative phase from the most advanced angle phase to the second
predetermined phase and does not bias the relative phase from the
second predetermined phase to the most retarded angle phase.
[0108] The biasing member biasing the relative phase toward the
predetermined phase in a range from the most advanced angle phase
side to the most retarded angle phase side may be constituted by,
for example, one torsion spring. However, since the biasing force
of the biasing member is most small near the predetermined phase,
it is difficult to maintain the relative phase reliably at the
predetermined phase. Further, as it is deviated from the
predetermined phase to the most advanced angle phase side or the
most retarded angle phase side, a restoring force of the biasing
member is increased. As a result, high oil pressure is needed to
displace the relative phase against the biasing force of the
biasing member, which tends to increase energy loss.
[0109] In the configuration, if it is constituted of two biasing
members, in which a biasing direction thereof is opposite to each
other, and the relative phase is biased to the predetermined phase
in cooperation with an acting force from two biasing members, the
relative phase can be maintained reliably at the predetermined
phase, for example, as compared with the above configuration in
which one torsion spring is installed.
[0110] In the configuration, when the relative phase is operated
from the predetermined phase to the retarded angle phase side or
the advanced angle phase side by operation of the oil pressure or
the like, for example, when the relative phase is operated toward
the retarded angle phase side, only the biasing force of one
biasing member acts in a state in which the biasing force of the
second biasing member is defined between the predetermined phase
and the most advanced angle phase by the second restriction
portion. Therefore, the relative phase can be displaced by
relatively small oil pressure.
[0111] In addition, in the configuration, in a state in which there
is no oil pressure or the like for performing displacement
operation of the relative phase, the first biasing portion does not
bias the predetermined phase from the first predetermined phase to
the most advanced angle phase, and the second biasing portion does
not bias the predetermined phase from the second predetermined
phase to the most retarded angle phase. As a result, in a case
where two biasing forces are not equal to each other through error
in manufacturing precision of the biasing members or the like, the
relative phase can be easily controlled at the original desired
phase without deviating to the retarded phase side or the advanced
angle phase side through the error.
[0112] The principles, preferred embodiment and mode of operation
of the present invention have been described in the foregoing
specification. However, the invention which is intended to be
protected is not to be construed as limited to the particular
embodiments disclosed. Further, the embodiments described herein
are to be regarded as illustrative rather than restrictive.
Variations and changes may be made by others, and equivalents
employed, without departing from the spirit of the present
invention. Accordingly it is expressly intended that all such
variations, changes and equivalents which fall within the spirit
and scope of the present invention as defined in the claims, be
embraced thereby.
* * * * *